Introduction. In today designing and construction, slabs laying on an elastic base are widely used as foundations of buildings and structures, road pavements, etc. Due to various impacts, the properties of a base can change over time, which inevitably affects the stress-strain state of a structure. Therefore, development of the analytical method for studying slab stress and deflection changes upon weakening a base the slab lays on is relevant.

Materials and Methods. The slabs on the elastic base were the objects of the research. The elasticity of a base was specified using the Pasternak model with two-bed coefficients. The derivation of the structure stress-strain state equations was presented taking into account the geometric nonlinearity. The system of differential equations was solved by the Bubnov-Galerkin method using approximative V.Z. Vlasov's beam functions. Such statement of a problem served to determine the stresses and deflections of a slab. The ratio determining the rate of fading of settlement deep inside a base was specified by a function enabling modeling various properties of a base beneath a slab.

Results. The results of deflection calculations obtained using the analytical formulas have been compared with the values obtained by means of software based on the finite element method. The possibility to model the decrease of base strength characteristics or base absence beneath a part of a slab has been shown. The values of deflections at various points of a slab in case of absence of the foundation beneath a part of a structure at the edge or in the centre have been investigated. Data obtained using the analytical formulas on the utmost values of a base beneath a part of a slab before its opposite edge begins to raise have been presented.

Discussion and Conclusion. The proposed statement of a problem can be used to investigate slab deflections and stresses occurring in its middle when the bearing capacity of a part of the subfoundation soil changes. The presented formula makes it possible to specify changes in the distribution of the bearing capacities of a base, it has several parameters offering wide opportunities for modeling the behaviour of a base. Graphs of deflection changes at different points of a slab are given, showing the possibilities to determine deflections of a slab on the elastic base upon base absence beneath a part of a slab at the edge (in the centre) or upon decrease in the strength of a base beneath a part of a slab. The size of the areas of base absence beneath a slab which keep the edge of a slab from raising is provided.

Introduction. The scientific problem lies in ensuring earthquake resistance of the buildings by optimizing design solutions, selecting the computational models and developing a methodology, which takes into account the nonlinear behaviour of the load bearing structures under the action of design-earthquakes and reference-earthquakes. For adhering to regulatory requirements in calculation of earthquake resistance of the structures of life-saving buildings, the nonlinear calculations of structures’ behaviour under intense seismic actions were made.

Materials and Methods. The calculations were made by the analytical method and the finite element method using the “STARK ES” and “LIRA-SAPR” software.

Results. The comparative computation results of the estimated multi-storey building dynamic model subject to the horizontal progressive dynamic action with the use of eigenforms in a linear formulation have been obtained. In addition, the results of dynamic calculation under the main and special combination of loads and corresponding combination of internal forces performed for the estimated structures of a multi-storey building with seismic isolation constructed in Grozny have been presented.

Discussion and Conclusion. The criteria for selecting the significant and excluding the insignificant forms of natural oscillations when performing the earthquake resistance calculations of structures with certain nonlinearities have been determined. The calculation results have demonstrated achievement of the required bearing capacity of a multi-storey building in the given calculation conditions.

Introduction. Natural and man-made slopes may lose stability in the event of change of the physical and mechanical properties of soils, seismic impact or additional loading. This often leads to the activation of landslide processes, damage of buildings, structures, roads and poses a threat to the safety and lives of people. Slopes in earthquake-prone places are the most dangerous and difficult for ensuring stability areas, therefore improving methods of engineering protection of slopes remains a relevant objective. The article studies the physical and numerical modeling of a sandy slope anchored by piles under the seismic impacts.

Materials and Methods. The paper uses the numerical methods to study the effect of earthquakes on sandy soil slopes reinforced with piles. The finite element method (FEM) is a widely used method for studying the interaction of structures and soil, especially in the complex combinations of loads and impacts. It accurately reproduces the complex behaviour of the massif, including stresses, deformations, horizontal and vertical displacements, as well as the nature of the collapse observed in the slope-pile system when it is subjected to seismic loads. The simulation of the specified above system is performed in a nonlinear formulation.

Results. The work of the pile allows transferring the part of the weight of the surface layers of the slope to deeper and more stable layers, which helps to maintain the stability of the slope. The parameters of the piles affecting the perception of seismic loads and the stability of a reinforced slope, including the type of pile, the method of its construction, earth[1]quake and slope parameters, are studied. The conducted study of the interaction of piles and dynamic loads makes it possible to improve design solutions for engineering protection of slopes from landslide processes in seismic places.

Discussion and Conclusion. As a result of modeling, it was found that piles can reduce lateral pressure on the soil, increase the shear strength of the soil and significantly affect the stability of the slope, especially in the event of an earthquake or flood. However, the efficiency of stabilization with piles depends on several factors, such as stiffness, distance between the piles, their length, location on the slope and connection to the foundation.

Introduction. Nowadays, production of high-quality building products with the given aesthetic properties is a relevant objective for the national ceramic manufacturing industry. The face brick still occupies one of the leading places in the up-to-date construction as one of the traditional building materials. However, at present a trend demand is being formed in Russia for the high-end brick with the explicit aesthetic properties: colour, texture, combinability. In GOST 530-2012 “Ceramic Brick and Stone. General Specifications" such characteristics of brick are not properly specified, neither definitions are given nor the criteria for assessing the quality are defined. Therefore, it is necessary to study the interrelation between the technological parameters of manufacturing and the aesthetic potential of a brick. On the example of the soft-moulded brick, we have studied the variants of colour decor (glaze) and textured pattern taking into account the direct “technology — aesthetics” correlation.

Materials and Methods. A soft-moulded brick of the multi-structural texture manufactured by “Tandem-VP” LLC (No[1]vocherkassk, Rostov Region, Russian Federation) was used in the research. The glaze for decoration was obtained on the basis of GP–2 grade frit of the Lysva Plant of Silicate Frits. When studying the interrelation between the aesthetics and technology of ceramic brick, the method of comparative analysis of decorative properties and the process of obtaining thereof was used, the historical regularities in the influence of technologies on the appearance of the products were identified. Based on the above, the classifications by types of decoration and textured surfaces of brick were developed, the terminology referring to the aesthetic criteria was extended making a certain step towards preparing the supplements to the existing GOST or developing a new one.

Results. The obtained variants of the glazed surface of the soft-moulded brick have different aesthetic effects depending on the composition of the glaze and the technology of its application: a smooth shiny surface, uneven surface with the unglazed fragments, the so-called “spotted” surface with an emphasis on the texture. A table of correspondence of the glaze application technology and the resulting surface has been compiled. The textured “pattern” of the surface of manually moulded brick has also been structured in a form of a table, and terminology has been assigned. These results will be taken into account when developing a technological processing line of soft-moulded brick decoration.

Discussion and Conclusion. The proposed classification frameworks allow us to identify the direct “technology — decor” correlation, the data can be adjusted and precised when applied to a specific ceramic production. It has been established that the following factors influence on brick surface obtaining the given aesthetic characteristics: clay raw materials, additives, brick moulding method, decoration material, decoration process, drying and firing. In this paper, we covered mainly the raw materials, moulding method and decor application method. Studying the interrelation between the aesthetic and technological properties has high research capacity, thus the topic will be investigated by us step by step. The conclusions drawn and the analysis of the results are of interest to the architects, technologists, production engineers, distributors and ceramists at large.

Introduction. The tower complexes of the Republic of Ingushetia are not only unique historical and architectural monuments, but also monuments to the history of “construction” of the region. In recent years, specialists are particularly interested in the masonry mortars used for bonding the stonework during building-up and repairing the towers. The study of the masonry mortars can provide the specialists the information about the materials used, ancient construction technologies, and, based on microstructural features, the age of the towers or their separate parts, which is especially relevant for the specialists in the field of materials science in construction, history of architecture, restoration and reconstruction of historical and architectural heritage. The aim of the research is to determine the composition of the masonry mortars in tower complexes of the Republic of Ingushetia and, based on the degree of crystallinity of secondary calcite, determine their age.

Materials and Methods. The objects of the research were the samples of masonry mortars taken from the tower complexes of Ehgikal, Targim, Pui, Leimi, Albi-Erdy, Ehrzi and others. The study of the chemical composition of the mortars was carried out according to the methodology of GOST 8269.1-97 “Crushed Stone and Gravel from Dense Rocks and Industrial Waste for Construction Work. Methods of Chemical Analysis”. X-ray diffraction phase analysis was carried out using the ARL X’TRA diffractometer with slit widths of 2-4-1-0.5. Measurement capacity provided by the ARL X’TRA diffractometer: angle range — 5–70°; speed: 5–6 deg/min; voltage — 40 kV; current — 30 mA. Diffractogram decoding was carried out in accordance with the appropriate methods by comparing with the similar studies, as well as with the use of international databases. Mineralogical and petrographic examinations were carried out using optical and digital microscopes of various modifications.

Results. The retrieved author’s research results are presented in the paper. The conducted research made it possible to establish that originally the overwhelming majority of ancient masonry mortars were represented by a mixture of air-setting lime and sand and gravel material or a mixture of air-setting lime and crushed clay slates. It was acknowledged that the degree of crystallinity of secondary calcite differs significantly and depends on the age of the tower stonework.

Discussion and Conclusion. The results obtained within this research can have practical value for carrying out the restoration works, and theoretical value for determining the relative age of the towers and their separate parts, which will significantly help to reconstruct the history of their construction.

Introduction. Obtaining the dispersedly-reinforced concretes with given properties is an important objective of materials science in civil engineering. Today, a great deal of experimental and theoretical research in the field of designing the compositions of dispersedly-reinforced concretes is being held. The majority of the existing works solve mainly the problems of modeling the structure of dispersedly-reinforced systems from perspective of fracture mechanics. However, an important objective is to determine a minimum reinforcement volume ratio of the composite material. The models developed by different researchers can be reproduced only for the limited recipe and technological factors. The aim of the present research is to improve the theoretical approaches and develop an analytical model for determining the volume of fiber in a composite. The paper proposes to investigate the properties of dispersedly-reinforced concrete from perspective of the percolation theory and fractal geometry.

Materials and Methods. Literature analysis of a significant amount of experimental data from information sources on the topic of dispersed reinforcement of concrete was carried out in the article. The statistical analysis and approximation of the obtained data was made within the research. Based on the obtained functions, the graphs of the dependencies of the fractal dimension of fiber on the analysed factors were plotted.

Results. The paper presents the theoretical grounds for determining the volume ratio of fiber concrete reinforcement using provisions of the percolation theory. The analysis and comparison of the experimental values of the reinforcement ratio with the theoretical values obtained by solving a problem involving spheres was carried out. A model for determining the fractal dimension of fibers in dispersedly-reinforced concrete was proposed. The available experimental data of different researchers was analysed to establish the degree of influence of the specific surface area of fibers on the fractal dimension parameter. Dependencies obtained by approximating the data using the least squares method were presented for the different types of fibers sorted by material.

Discussion and Conclusion. It is proposed to determine the fractal dimension of the composite material by the analytical method. The influence of the relative length of the fibers and their specific surface area on the fractal dimension parameter was shown. The research in this direction may be of certain scientific interest in terms of forecasting the properties of dispersedly-reinforced concretes and design of their compositions. This, undoubtedly, will contribute to further development of the theoretical concepts of creating the fiber reinforced concrete composites.

Introduction. The problems of resource and energy saving during production of cements and concretes on their basis are of great importance in the world. An important trend in solving these problems is the development of green cements, which contain various mineral additives of natural and anthropogenic origin. The advantages of the green cements compared to the clinker-based cements are revealed from both the environmental point of view — reduction of carbon dioxide emissions into the atmosphere, use of the industrial by-products, and the technical point of view — improvement of the technological properties of concrete mixes, improvement of the physical, mechanical and operational properties of con[1]cretes. At the same time, replacement of the clinker component in Portland cement by the mineral components leads to the change of the physical and mechanical properties of cement, including that taking place during the “caking” process in conditions of interaction with the environment. The research presented in the paper aims at studying the effect of long-term storage of plain cements and green cement composites in conditions of free interaction with the environment on the physical and mechanical properties of the cement stone.

Materials and Methods. Various types of cements were used in the experiments. Green cement composites were obtained in the laboratory by intergrinding with the slag and fly-ash respectively. To improve the grinding process and inhibit the sorption process, a grinding intensifying agent was added into the composition of green cement composites. The impact of the environment on the cement sorption process was assessed by measuring indirect parameters: specific surface area, angle of natural repose, bulk density and cement stone compressive strength.

Results. The obtained results indicate that the specific surface area of cement samples stored in the open air for 30 days reduces significantly due to the “caking” process, on average by 25% in type I cements, whereas in green cement composites this process is less intense and amounts to 15%. A similar consistent pattern is observed when measuring the angle of repose and bulk density. The decrease in the angle of repose and high values of bulk density for type I cement are related to the active sorption of moisture from the environment, which leads to the formation of hydrate “bridges” upon interaction of particles. Compared to the control samples, the compressive strength in the cement stone samples tested at the age of 28 days of curing decreases on average by 25–30% in type I cements and by a less extent of 15–20% in green cement composites.

Discussion and Conclusion. When storing different types of cement in conditions of free interaction with the environment, moisture is sorbed and the hydrate “bridges” are formed on the surface of the particles. This process goes more intensely in type I cement due to the highly active surfaces of its particles, which hydrate faster, resulting in a decrease of cement activity by 30%. At the same time, the green cement composites lose their activity less significantly – by 20%. This consistent pattern can be explained by the less active surfaces of the particles of mineral additives included into the composition, as well as by addition of a grinding intensifying agent into a composition.

Introduction. In the context of global competition, the high-quality products of the enterprises from the developed countries occupy the leading positions in the world markets, which causes the growth of demand for graphite products. Graphite, due to its unique properties, is used in various industries, including the production of high-temperature furnaces, electrodes for welding and cutting, as well as in battery production technology. The aim of the study is to investigate and analyse the properties of graphite electrodes, their application in welding processes and to evaluate their competitive advantages compared to other types of electrodes. The work is aimed at identifying the features of using graphite electrodes in various industries, such as steelmaking, metallurgy and chemical industry, as well as studying their physical and chemical properties, which make them efficient for the use at high temperatures and in corrosion conditions.

Materials and Methods. The research was carried out with reference to the Tazkazgan graphite mine located in the Central Asia. The chemical composition and carbon content of the graphite ore were analysed, which made it possible to classify it into groups by quality. It was found that the ore contains up to 51.8% of graphite and other components that affect its properties.

 Results. The obtained data show that graphite from the Tazkazgan deposit can be classified by carbon content into low-carbon, medium-carbon and high-carbon, which allows it to be recommended for the production of welding electrodes. The chemical composition of the ore indicates its capacity to be used in various industrial applications.

Discussion and Conclusion. Graphite materials mined at the Tazkazgan mine are attributed with the significant quality characteristics, which make them competitive in the market. Further research should focus on optimising processing and application of graphite in new technologies to make the most of its unique properties.

Introduction. A financial component of the project result affects considerably the implementation of the new technologies and is, among other things, a fundamental factor in assessing project’s efficiency. In most cases, when developing a project for the production of works, the project designers do not take into account the specific regional features, for example, when building the housing and welfare facilities for the needs of gas industry, they do not use an integrated approach, therefore, the final costs do not match the initially planned ones.

Materials and Methods. The article studies the main factors affecting the cost of a project, the influence of logistics on the project cost reduction and the most significant logistic problems to be solved. The typical risks and planning mistakes in the development of a project for the production of works have been investigated.

Results. A comparative analysis of the main costs required for the successful development of a project, the project logistical tasks, the standard and proposed calendar plan of the production of works based on the common decision-making was made. The main indicators having the foremost impact on the final cost of construction of a facility were identified. The main steps of calculation fostering the optimisation of target cost accounting were formulated.

Discussion and Conclusion. Net income was determined to be the main indicator of project management efficiency, i.e. obtaining positive result of company’s financial and construction activity. The balance of all incoming funds and required expenses was compiled: expenses and payments, including the ones allocated to the construction of a facility, as well as taxes per certain moment of facility construction. In the context of full life cycle of an object of construction, an assumption was made about inefficiency of panel buildings compared to the quick-assembly modular buildings due to the issues of transportation, erecting, subsequent operation and, eventually, after construction dismantling of the former. The most simplified solutions were proposed.

Introduction. The present-day construction market in Russia is rapidly developing, especially the life cycle managing technologies of buildings and structures. Building information modeling technologies are used in the large-scale national projects throughout the country, which fosters implementation of the new approaches and methods to developing the information models. Information growth and development rates undoubtedly affect the quality of the implemented projects, especially in terms of parameterization and classification of the original data, which in turn contributes to the emergence of the new and revision of the old approaches to handling the information parameters. The use of building information modeling in modern design requires revision of the approaches to the analysis of the original data and the results of work throughout a life cycle of a capital construction facility. This directly induces a need to process a large amount of information, especially at the initial stages of project development. The aim of the present research is to identify dependencies among the information parameters, and determine the distribution of a random variable using the Pearson criterion. The technologies are developing worldwide fostering implementation of the new approaches and design methods in the construction industry. Furthermore, due to the Russian Federation Government Regulation No. 1431 of September 15, 2020, which directly binds to use the software packages for three-dimensional design, there arises a need to have the normative regulation not only for the three-dimensional models, but also for the information parameters under-lying these models.

Materials and Methods. The research presents the theoretical and practical results obtained during implementation of a BIM-based project of a facility located at VDNKh in Moscow (the Pavilion No. 34 “Kosmos” (Space)) on using the Pearson criterion for assessing the number of information parameters for subsequent use in a digital passport.

Results. The mathematical calculations of the generalised data obtained within the research allow the authors to confirm the hypothesis of the uniform distribution of a random variable, which makes it possible to predict the future results and integrate them into the future objects of capital construction planned to be built with the use of building information modeling for maximizing efficiency of this technology in the future.

Discussion and Conclusion. The obtained values allow us to conclude that the distribution function of a random variable in uniform distribution can be used to approximate the empirical distribution under study. The calculation results allow the authors to make an assumption about full appropriateness of the uniform distribution law application for assessing the number of information parameters required for a digital passport.